1. Field of the Invention
The present invention relates to durable hydrophilic fibers, and more specifically, to durable hydrophilic fibers, and cloth articles and molded articles obtained by using the fibers which are useful for surface materials for paper diapers, sanitary napkins, etc. mainly in the field of hygienic materials, useful for form retaining goods and molding retaining goods of moisture absorbent articles, and useful for industrial and medical wiping clothes.
2. Description of the Prior Art
A paper diaper or the like is formed with three layers, i.e., a surface material, an absorbent material and a back material from the side with which the skin touches when worn. The surface material need to have a water permeability by which a liquid to be absorbed is rapidly transmitted to the absorbent material, and a dry touch property by which the absorbed liquid is prevented from back flowing to impart the skin dry feeling. Hydrophilic property is preferred in order to improve the water permeability, and hydrophobic property is preferred in order to improve the dry touch property. For achieving the aforesaid object, nonwoven fabrics are used in which a small amount of surfactant is adhered to fibers formed of a polyolefin resin or a polyester resin (Japanese Patent Application Laid-Open No. 63-6166 Publication and Japanese Patent Application Laid-Open No. 63-49158 Publication).
In the surface material using the fibers to which the surfactant is adhered as described above, when liquids are absorbed once or twice therefrom, the surfactant flows out and the water permeability rapidly lowers so that the liquids remain on the surface material, resulting in imparting unpleasantness. As the material which reduces the flow-out of the surfactant adhered to the fibers and in which even if water is permeated repetitively, the hydrophilic property is not lowered, nonwoven fabrics formed of durable hydrophilic fibers to which is adhered a surfactant containing a water soluble modified silicone have been known (Japanese Patent Application Laid-Open Nos. 63-303814, 1-148879, 1-148880, 2-169774 and 3-59169 Publications).
However, these nonwoven fabrics or woven fabrics formed of the durable hydrophilic fibers to which the surfactant is adhered were good in the durable hydrophilic property but were suffered from a problem in that since the water soluble modified silicone is contained as an essential composition, the friction of fibers reduces, the fibers constituting a fiber laminate such as nonwoven fabrics slips, and the strength of web lowers and the strength of a fiber laminate such as nonwoven fabrics lowers. There was a further problem in that also in the wrapping process of the goods of the obtained cloth articles, since the smoothness between the cloth articles is so high that the wrapping form of the goods is not stable.
In Japanese Patent Application Laid-Open No. 3-50030 Publication, there is proposed a method for imparting hydrophilic property for adhering a mixture of alkyrol amide and an alkylene oxide additive of a compound having an active hydrogen or a surfactant such as alkylphosphate to polyolefin fibers. However, in this method, the durable hydrophilic property is not sufficient, and the electric resistance is not good.
It is therefore an object of the present invention to provide durable hydrophilic fibers, and cloth articles and molded articles using said fibers, which have the durable hydrophilic property raised by the prior art as described above, which reduces the slip of fibers not to lower the strength of a fiber laminate such as nonwoven fabrics.